


Happy Birthday, Detective Inspector

by MoonRiver



Category: Sherlock (TV)
Genre: Accidental Voyeurism, Anal Fingering, Birthday, Birthday Sex, Blow Jobs, Couch Sex, Drunk Sex, Group Sex, M/M, Making Out, Oral Sex, Sexual Content, Threesome, Threesome - M/M/M, Voyeurism
Language: English
Status: Completed
Published: 2016-08-26
Updated: 2016-08-26
Packaged: 2018-08-11 02:49:07
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,278
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/7873222
Author URL: https://archiveofourown.org/users/MoonRiver/pseuds/MoonRiver
Summary: <blockquote class="userstuff">
              <p>“Come on, Detective Inspector,” Sherlock said with a sly grin and a twinkle in his eye. “What’s a little sex between friends?"</p><p>Sherlock and John invite Greg to join in on his birthday.</p>
            </blockquote>





	Happy Birthday, Detective Inspector

As Greg stirred awake on the night of his fifty-first birthday he was immediately hit with nausea and a sour feeling in his stomach. It was yet another grueling reminder that getting older meant he needed to give up the drinking habits of his youth- of course the whole pizza he ate entirely by himself didn't help either. His birthday night had consisted of a night in with Sherlock, John, and a few mates from work who over to watch the match and drink. His colleagues had all headed home around eleven, but Sherlock and John hung around for one final drink. In the end the three of them ended up passing out on the oversized sectional Greg had bought as a birthday present to himself, and it took him a moment to remember where he was when he came to.

He was about to roll over and drag himself to bed when he heard a low moan from the other end of the sofa. His heart stopped. He’d had enough sex to know those low moans, the quiet gasps for breath, from anywhere.

Sherlock and John were having sex.

In his flat.

Right on this very sofa.

Greg wasn’t sure if he felt angry, disgusted, or…aroused. His stomach felt a bit tight all of a sudden, and his cock twitched. He held his breath and closed his eyes, horrified at the thought of the two of them finding out he was awake and listening to them.

“Christ!” Sherlock’s voice hissed.

His voice was barely above a whisper, but it seemed to ring loud in Greg’s ears. He had to admit he had more than a few wet dreams involving Sherlock since he met the younger man, but he would never admit it. Very few people knew he was bisexual, and he had been even shyer about it since his divorce. How would it look if he was suddenly sleeping around with younger men after being married to a woman for ten years?

The noise of lips sucking against skin became obvious, and he realised John must be sucking Sherlock’s cock, and god if that image alone didn’t make his own dick harden.

 _“Yes!”_ Sherlock whispered.

“Shh!” John shot quietly. “He’ll hear you.”

Ignoring him, Sherlock let out another moan. The sound went straight to Greg’s cock.

“Told you we should have gone to the bedroom,” John muttered.

“You can’t have sex in another man’s bed on his birthday!” Sherlock protested.

And now Greg was imagining the two of them fucking on his own mattress, and he was surprised to find himself thinking he wouldn’t mind that.

He wouldn’t mind watching that.

_I shouldn’t be having these thoughts._

He closed his eyes even more tightly...

“Fuck,” John whispered; the sound of a zipper opening followed.

The room was silent for a few moments which only made Greg more anxious because he knew that meant John’s lips were wrapped around Sherlock’s cock, sucking him down. He could hear his consultant’s breathing becoming more erratic, and he had to bite down on the pillow his head was rested on to keep from moaning himself.

“For god’s sake Greg, join us already before you burst.”

A gasp escaped him at Sherlock’s demand, but he couldn’t bring himself to face the pair. He felt ridiculous, laying there and listening to his mates suck each other off. Why hadn’t he just fallen back asleep and pretended like nothing had happened?

A pillow was thrown at him, and Greg finally let out a groan.

“God, Sherlock!” He whined as he rolled around at last. The bulge in his trousers grew as his eyes automatically found Sherlock’s thick cock. “Why are you two having sex on my sofa?”

Sherlock simply shrugged before throwing himself back against the sofa and thrusting his hips up into John’s mouth.

“Couldn’t wait,” he muttered.

The doctor popped off his boyfriend’s cock to gasp for air; he pumped Sherlock’s cock as he added:

“He insisted you’d be passed out until morning.”

“Well I…wasn’t,” Greg snapped.

He swallowed hard. His throat had gone dry. He was very uncomfortable sitting on the sofa, having to just watch and knowing he could never dare to think of participating.

“Or just watch, if that’s your thing,” Sherlock said. “Christ, _John_!”

“Bloody hell,” Greg muttered as John mouthed at Sherlock’s balls and rubbed his hands along his thighs. “You’re…you’re okay with this, John?”

“I’ve always thought you were hot,” John confessed.

“Come on, detective,” Sherlock said with a sly grin and a twinkle in his eye. “What’s a little sex between friends? John’s very good at this, if you want to see for yourself.”

John’s eyes flashed up to him, challenging him, and Greg knew he had to give in.

“Oh what the hell,” he muttered as he stood up. “It _is_ my birthday…”

“Yes,” Sherlock agreed. “I believe spankings are usually required on birthdays, are they not?”

Greg’s eyes went wide, and Sherlock just laughed.

“Later,” Sherlock offered. “Sit.”

He nodded to the empty spot on the sofa next to him; Greg’s legs felt a bit weak as he sat down beside Sherlock. His consultant wasted no time reaching over so he could run his hands up his leg. He shivered at his touch: so light and graceful.

“Have you ever been with a man before, Greg?” Sherlock breathed.

His breath was hot against Greg’s face as his lips graced his cheek with a surprisingly gentle kiss.

“Yes,” Greg replied, his voice shaking.

Sherlock’s hands palmed his cock through his trousers, and Greg’s eyes fell closed.

“A bit…starved, aren’t you?” Sherlock asked. His eyes glanced down to Greg's zip. “May I?”

Swallowing nervously, Greg could only nod. He kept his eyes closed as Sherlock’s warm hand snaked into his pants and caressed his cock. It was true: he hadn’t been with many men or women since his divorce. He used work and long shifts an excuse for not having time to date, when in reality he secretly longed to be wanted by someone else again. He secretly longed to have company- to have someone to come home to. And while Sherlock and John couldn’t give him that, if he could just feel the thrill of sex again, even for just one night, maybe it could give him the confidence he needed to…

“Oh!” Greg gasped as Sherlock’s fingers teased his balls.

All the while Sherlock’s lips danced along his jaw, down to his neck and nibbled a tiny bite just beneath his collar.

“Pull them down all the way,” Sherlock growled into his ear.

He didn’t hesitate to obey as he shoved his trousers down to his ankles and kicked them off to the floor. He noticed Sherlock and John were both fully clothed, save for the cock hanging out of Sherlock’s trousers. Although he felt exposed he also felt…edgy. Sexy. And it felt silly to admit it at his new age of fifty-one years old but he _needed_ to feel that way. 

Suddenly Sherlock buried his head into Greg’s shoulder and his body tensed.

“Oh god… _John_!” Sherlock cried against his skin.

Greg looked down to realise Sherlock was coming, and John’s eyes flashed up to him again, his lips fixed in a devilish grin as he swallowed down every last drop. He held onto his consultant as he breathed heavily against him, coming back down to earth.

“Well,” Sherlock said with a wicked grin as he sat back.

“That was…some show,” Greg said, suddenly feeling a bit awkward and very out of place.

Christ…what was he doing? He was far too old to be messing around like this!

And yet…John’s eyes were still wild as he crept upward toward Sherlock and kissed him madly, with more passion than Greg had ever seen two people kiss with in real life. Their lips danced together, their tongues fought. He hadn’t felt this…turned on since long before his marriage ended.

“Now you’re just showing off,” Greg muttered.

Grinning, Sherlock nibbled at John’s ear and placed a trail of kisses down his jaw.

“I think Greg is feeling left out,” John teased as he unzipped his own trousers

“I think you both are,” Sherlock said he hopped off the sofa. Greg shuddered as John scooted next to him, and as his consultant knelt down on the floor and his hand glided up his thigh he let out a nervous breath. “Stop panicking. Relax. You need this. You _want_ this.”

He gasped as a cold hand fell on his cock, and when lips closed in around the head his body froze up.

“Greg,” John breathed beside him. “Relax.”

A hand cupped his cheek, and he hardly had time to react before John’s lips were on his.

 _“John,”_ Greg murmured, confused, startled, and yet… _god_ John was a good kisser.

“Just relax,” John whispered between kisses.

Closing his eyes, Greg forced himself to do just that: relax. It felt strange, feeling another man’s lips on his, especially when that other man’s boyfriend was watching him closely as he sucked down his cock. But as John’s tongue slipped between his lips and dove into his mouth he finally found himself able to give in. Meanwhile Sherlock’s mouth was working wonders on his cock; he seemed to know exactly how he liked it.

 _“Yes,”_ he sighed, holding onto John for a moment as he came up for breath. “Jesus, Sherlock.”

Suddenly Sherlock’s lips jumped to his balls and sucked, leaving Greg breathing hard into John’s shoulder. The doctor’s hands grabbed at his back, his lips sucked at Greg’s jaw, his neck. There would be a nice red mark there tomorrow.

Without warning Sherlock popped off his cock and wrapped his lips around John's instead. Greg almost wanted to protest, but when he heard John moaning against his skin he thought he could live with it for a bit.

It was his turn to please, he realised.

But once again his body froze, and he had to remind himself that he had done this before. Maybe not with Sherlock and John, maybe not in a threesome, but he had pleased people before. Plenty of people. He knew what people liked- what _men_ liked. He could do this.  

He placed a hand on John’s chest and let out a long breath before swooping in and kissing him. It wasn’t messy, it wasn’t wild: it was slow and sensual. John didn’t make a sound but he breathed into it, kissing him back and tightening the grip of his hands against his back.

“Sherlock,” Greg announced. He took in a few breaths before looking up, meeting John’s eyes. The doctor nodded. He wanted this. Greg wanted this. “May I?”

“Oh yes,” Sherlock replied.

He noticed for the first time Sherlock was slurring his words a bit; they were all probably too drunk to be doing this. His own head was spinning as he turned back to John. His heart was pounding. He felt a bit dizzy and the room seemed to spin around him; this was all just too surreal.

He was about to have sex with another man’s boyfriend.

In front of said other man.

And apparently, this was perfectly okay.

Well, he should make sure it was okay with John.

“John?” He asked softly, his hand still rested on the doctor’s chest.

“Yeah,” John nodded. “I want you too.”

He wanted him. _Wanted_ him!

And god if that wasn’t enough to push him over the edge.

Gently, slowly, he pushed John down onto the sofa. He knew John had been messing around with Sherlock for far too long already tonight and he wouldn’t last very long- this time around, at least. And frankly, his own cock was so hard that just the friction from rubbing against John’s body as he lay over him was nearly enough to set him off.

Greg began a trail of kisses from John’s jaw, down his neck, down his chest, and finally to his cock. He drew in a deep breath before taking him down, sending John’s back arching up from the sofa. He licked around the head and in one daring move, reached out to Sherlock with a finger of his left hand.

Sherlock seemed to get the memo immediately. He placed his lips around the finger and sucked hard. He knew they couldn’t go all the way right now, but he knew what would feel _perfect_ along with that blow job.

As he began licking down the length of John’s shaft he gently began fingering at his hole.

“Oh god!” John moaned as he threw his head back against the sofa.

John’s knees folded up to his chest, giving Greg more room to work. He pressed his finger in, knowing that even if John couldn’t enjoy the feeling of Greg being inside him, he would most definitely enjoy this.

“Fuck yeah!” The doctor whispered as Greg’s mouth engulfed his shaft.

His confidence was coming back to him now. He could feel John’s cock thrusting against his throat and god if this wasn’t one of the hottest things he’d ever experience. His hand jumped down to rub his own cock, which was desperate for attention. Then he brought it back up to press into the doctor once again.

“Greg,” John breathed. “That’s it. Like that.”

He pressed his finger in further, opening John up a bit more, and Greg moaned around his cock just thinking of the possibilities to come. Maybe Sherlock would let him fuck John sometime, for real. He could just imagine the warm tightness of his cock inside John’s arse, thrusting in and out…

Greg pushed in two fingers and John whimpered, _whimpered_ , as he scissored his fingers and sucked his cock. Meanwhile Sherlock leaned over to tease his boyfriend’s nipples with his tongue. First one, then the other.

“God,” John hissed, throwing his arm over his face. “I’m gonna cum.”

“Do it,” Sherlock whispered as he kissed his way up John’s chest. “Greg…”

His consultant sat back to whisper something into Greg’s ear, and what he said surprised him and turned him on so much that he leaned up in shock. Momentarily he pulled off of John’s cock, just long enough for the doctor to cum.

 _“Oh god!”_ John moaned. “God, Greg…Sherlock.”

It was all he could manage before coming over Greg’s lips, his cheek, and collapsing back into the sofa.

“Fuck yeah!” Sherlock hissed before swooping in, kissing Greg on the lips before he could protest.

“Jesus!” John breathed, a grin slipping across his face as he let out a laugh. “Greg that was…that was pretty incredible.”

Although he could feel his face burning from adrenaline, desire, and even a bit of embarrassment, Greg still found himself grinning. He let out a breathless laugh before finding his lips captured now by John’s. As they pulled away his head spun, and he was painfully aware of how hard he was.

“Mmm, guess it’s your turn,” Sherlock slurred.

“Dear god, please,” he groaned as Sherlock lowered himself back to the floor.

He hissed as soft lips graced the head of his cock, but his consultant didn’t waste too much time being delicate. His tongue darted out, lapping up the side of his shaft. Greg grabbed onto a sofa pillow; it had been so long since someone had done this to him and his senses were going into overdrive. Beside him, John climbed up on the sofa and brushed his lips against his neck. Without even thinking about it Greg tilted his head so he could kiss the doctor. A soft groan escaped his lips; his breathing became erratic as Sherlock took his dick in his mouth.

“Oh Jesus,” Greg blurted out against John’s lips.

The doctor continued to kiss him, their lips danced frantically. They were both far too drunk to be able to coordinate well- and he knew he wouldn’t last. Reaching down he rubbed his balls, trying to hint to Sherlock what he liked. The younger man caught on quickly and he took over.

“Fuck!” Sherlock hissed.

He couldn’t concentrate anymore. His head fell against John’s shoulder and the doctor placed trails of kisses along his shoulder blade as he finally came, shaking as he did.

“That’s it,” John whispered. “God, Greg.”

As he collapsed back against the sofa he felt lifeless. He wasn’t sure how he’d ever move, but then Sherlock climbed on top of him, positioning himself so he could swoop down and capture his lips in his own kiss.

“Happy birthday, Detective Inspector,” Sherlock murmured into his ear.

A sloppy smile crossed his face as Sherlock slipped off him, and the three of them shared a laugh as what they had just done truly began to sink in.

“How long have you wanted to do that?” Greg teased.

Sherlock’s usual dark and ominous eyes lit up; there was a spirit about the man tonight he rarely saw. His usual confidence and strength was there, but he was _carefree_. He was daring. He was…a normal, horny, bloke.

And that was a quite refreshing version of Sherlock to see.

“You’re an attractive man, Greg,” Sherlock offered. He was still slurring his words and his eyes were beginning to droop to a close against his will. Greg couldn’t help but to wonder how they would all handle this in the morning, once the booze wore off. “And John is surprisingly adventurous when it comes to his sexual kinks.”

The doctor snorted.

“Sherlock!” He whined. With a laugh, John explained: “Sherlock didn’t believe that I would do a threesome with him.”

“So I’m a dare?” Greg teased, only _slightly_ hurt.

“Well that- and I can’t tell him how many times I’ve caught him _staring_ at you,” John grinned. “So I told him if the moment ever presented itself…”

“And Christ did the moment present itself,” Greg laughed. “You two are bloody hot together.”

A sly smile crossed Sherlock’s face as he leaned over, and Greg let out a satisfied sigh as he kissed his consultant one last time.

“Right,” Greg announced; it was becoming apparent to him just how much he was slurring his own words. “You two are staying the night, yeah? Cause I really can’t send you off in a cab in this state, people will talk.”

John let out a snort, and it had occurred to him he had never actually seen the doctor drunk. Sherlock- Sherlock he had mostly seen high- but he usually only saw John Watson when he was at his most professional at crime scenes. It was nice, seeing the two mates being so intimate, so _normal_.

“Is that an invitation to join you in bed?” John asked.

Laughing, Greg nodded.

“I’m too fucking old for shagging on the sofa, let alone sleeping.”

The room swam before him as he stood to his feet; the blood rushed to his head and he let out another laugh at how absurd this all was. Excitement- and a bit of anxiety- rushed through him as they trudged their way into his bedroom. Would they do it again? Could they maybe do _more_? Did he have the right to ask for that?

As Sherlock threw himself on the bed so that he took up a whole half of it Greg grinned. He couldn’t help but to imagine how his consultant would look, underneath him, as he took him…

But as soon as his body hit his bed he let out a soft moan and sleep began to rush over him. He hardly had time to pull the covers over the three before they all drifted to sleep.

**Author's Note:**

> I've been wanting to add to the Sherlock/John/Greg threesome category for awhile now. Hope you enjoyed it :D Thanks for reading!


End file.
